Is the market "all AI" right now?

If you've scrolled past any finance headlines or social media lately, you've probably seen some version of this sentence: AI is breaking the market's roof. Sure, it sounds dramatic, but it's actually one of the easiest financial ideas to comprehend once you break it down and it's a good one to know (even if you're nowhere near ready to invest yet!).

Here's the simplest way to see it - since May 2024, the S&P 500, the index that tracks 500 of the biggest companies in the US, and one of the most common ways people measure "how the stock market is doing" has gained roughly 142%. Sounds huge, right? But if you take AI-related companies out of that index completely? The gain drops to around 16%...ouch.

Wait, so a few companies can move an entire index?

Here’s an analogy. Imagine your class average on a test is really high, because three students scored 100%, while everyone else scored around average or even low. Yes, the class average looks great, but it's not actually telling you the full story.

That's basically what's happening with the market right now. AI companies now make up somewhere between ~40–45% of the entire S&P 500's value. It’s the highest it has ever been (yet)! A small handful of companies are pulling the "average" up so much that they're hiding how the rest of the market is actually doing.

That's kind of where the market is right now. Nobody fully knows yet if this path leads somewhere real, or somewhere we'll have to backtrack out of.

So is this a good thing or a bad thing?

Honestly? It's a bit of both, and that’s the point where a fundamental understanding is needed, rather than just reacting to headlines with your eyebrows up your forehead.

The case for it being a good thing: Simply put, AI is changing how companies build products, cut costs, and make decisions. Some of that growth reflects real and useful technology, not just hype around AI bringing us to doomsday and people not having jobs.

The case for being cautious: When the market's performance depends on one theme so heavily, it means the market is much more fragile than it looks. If confidence in AI companies drops even a little it won't just affect those companies, it could drag the whole index down with it. It's a real-world lesson in diversification. If you’ve been following along with Monflow, you know how important it is -  if your entire future portfolio ever leaned as heavily on one sector, just as the S&P 500 currently leans on AI, that's a risk worth knowing how to avoid. Doesn’t sound so nice now, does it?

This is sometimes called concentration risk - when too much of your (or the market's in this case) value depends on too few things.

Why this actually matters for you?

You don't need a portfolio to care about this. The main reason for simply understanding the concept is the fact that it teaches you to look past headlines. "The market is up!" and "a handful of companies are up" are two very different statements, and now you, dear reader, know how to tell the difference.

It's a good reminder that averages can hide the full picture not only in investing, but in a lot of areas of life.

Don’t get me wrong - you don't need to have an opinion on whether AI stocks are a "bubble" or a "breakthrough" to get something useful out of this. The real lesson is far more simple: numbers that look impressive on the surface are always worth a second look at what's actually behind them.

That's a habit worth building now, long before you ever open an investing app.